Riot should create a negative to sitting under tower all game

Why is there no negative in this game mode to sitting under towers all game, nothing is more frustrating than staring at a team of all range sitting under a tower poking all game, then just punishing anyone who dares engage. This is a problem in only this mode because they give every poke champ a card that buffs sitting at range or just a in general range buff, no one wants to watch 5 people sit under a tower for 30 minutes then take every tower and sit as far back as possible